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701MAME ry �. J �?. � r.:�.ai ".. .�+' �g1 ��_ ff r��-... :?�+l' 2,.. .'.P. SSB 91-1438 Thrifty Oil Cotnpagv Station Page 11 7647 Pacific Avenuc Stockton.California feet, where the highest concentration (0.78 mglkg) was indicated. Toluene and ethylbenzene were detected in samples to depths of 50 and 45 feet,respectively. Xylenes were detected to a depth of 50 feet. soil les Boring B-2 (MW-2): Gasoline range hydrocarbons were detected etect da in nslwere de ected analyzed, except for the 5 foot sample- The highest TPHg respectively)'dtested in samples from depths of 20 and 45 feet (380 mg/kg and 560 mglkg, Benzene was detected in samples from 20,30,45,and 50 feet below site grade(BSG),with the highest concentration at 45 feet (4.2 mgfkg). Toluene anu ethylbenzene were detected at concentrations above the method detection limit for all samples except those collected at 5 and 60 feet. Boring B-3 (MW-3): Gasoline range hydrocarbons were detected only in the samples taken from 50 and 55 feet,with TPH9 concentrations of 6.5 and 1.3 mg/kg, respectively- , concentrations were a maximum of 0.30 mglkg feet. Toluene,ethylbenzene, at SS and xylenes were also detected at concentrations above the method detection limit in both samples. Boring B 4 (MW-4) Gasoline range hydrocarbons were detected in the 50 and 55 foot were detected only in the 55 foot samples. TPHgj toluene, ethylbenzene, and xylenes sample. Benzene was detected in samples from both 50 and 55 feet. All concentrations indicated were trace. The results of the chemical analyses indicate that the highest concentrations of gasoline range petroleum hydrocarbons in soil were found between the depths of til and 45 feet in boring B-2. The highest concentrations detected in boring B-1 were between':5 and 45 feet, but were substantially lower than those detected in boring B-2. only trace concentrations were detected in borings B-3 and B-4r The concentrations of compounds detected in soil in borings B-3 and B-4 are likely due to the lateral migration of fuel constituents on historically shallower ground- _ water levels. Gasoline range organics were not detected in the sample from baring B-2 analyzed by the TCLP extraction methods. The concentration of barium detected by the same procedure does not exceed regulatory levels to determine if a waste exhib:Is the characteristic of toxicity set deral Regulations) 261.24. Detected concentrations of total lead in forth in 40 CFR (Code of Fe SSB ENVIRONMENTAL CONSULTANTS-INC.